Natural gas streams that contain H2S must be treated to remove the H2S before the gas is suitable for transportation or sale. When the H2S concentration is sufficiently high, the sulfur cannot be emitted into the atmosphere due to safety concerns and environmental regulations. Instead, the H2S is processed into a liquid or solid product. For example, chelated metal processes can be used to convert H2S into elemental sulfur. One problem with these processes is that the elemental sulfur becomes contaminated with the extraction solvent and side reactions, e.g., chelated metals, thiosulfates, and bicarbonates, which make the sulfur a non-marketable, worthless waste product. Some contaminants can also make the sulfur a hazardous waste.